Semiconductor device in a recess of a semiconductor plate

ABSTRACT

A semiconductor device provided with one or more semiconductor pellets arranged on the bottom surface of a recess produced along a surface of a semiconductor plate having wirings arranged on the surface thereof, wirings extending toward the surface of the recess, and the recess being buried with a layer of a resin which is inclined to inflate, while it is hardened, resultantly producing a stress in the resin layer to expand toward the side wall of the recess engraved in the semiconductor plate, resultantly preventing breakage from happening for an interface between the side wall of the recess engraved in the semiconductor plate and the surface of the resin layer contacting the side wall, and remarkably improving the thermal conductivity efficiency to reduce the magnitude of a temperature rise of the semiconductor device, resultantly preventing a delay from happening for the operation speed of the semiconductor device.

This application is a Divisional Application of prior application Ser.No. 09/221,149, filed on Dec. 28, 1998 now U.S. Pat. No. 6,340,842.

FIELD OF THE INVENTION

This invention relates to an improvement applicable to the structure ofa semiconductor device which includes one or more semiconductor pelletshaving at least one semiconductor device element disposed therein andbeing mounted on a printed circuit board and being covered by a resinlayer and to a method for producing a semiconductor device free fromdrawbacks accompanying the structure of a semiconductor device whichincludes one or more semiconductor pellets having at least onesemiconductor device element disposed therein and mounted on a printedcircuit board and being covered by a resin layer.

BACKGROUND OF THE INVENTION

Available in the prior art is a semiconductor device illustrated in FIG.1. Referring to the drawing, a semiconductor pellet 22 in which at leastone semiconductor device element has been produced, is mounted on aprinted circuit board 11 made of a glass epoxy resin complex et al. andwhich has bonding pads 20 thereon connected by bonding wires 26 with thecounter parts 24 produced on the semiconductor pellets 22, which arecovered by a resin layer 28. The printed circuit board 11 has solderbump electrodes 16 produced thereunder. When such a semiconductor deviceis mounted on a larger printed circuit board or a mother board 14, as isshown in FIG. 2, the solder bump electrodes 16 are connected, employinga melting process, with corresponding electrodes 50 printed on thelarger printed circuit board or the mother board 14.

The foregoing semiconductor device available in the prior art isinevitably accompanied by drawbacks tabulated below.

1. The adhesion is inclined to be broken for the interface between thesemiconductor pellets 22 and the resin layer 28, due to thermal stresscaused by the difference in the coefficients of thermal expansion. Thisdrawback readily happens during the process for mounting thesemiconductor device on the larger printed circuit board or the motherboard. This drawback readily allows humidity to contact metal parts ofthe circuit of the semiconductor pellets 22, resultantly causing themetal parts of the circuit to be corroded.

2. The heat generated in the semiconductor pellets 22 is dissipatedtoward the larger printed circuit board or the mother board through theprinted circuit board 11 made of the glass epoxy resin complex et al. ofwhich the thermal conductivity is less, resultantly causing a less gradeof the thermal dissipation efficiency for the semiconductor devicehaving the foregoing structure. This drawback readily causes aremarkable rate of delay in the operation speed of the semiconductordevice.

OBJECT AND SUMMERY OF THE INVENTION

Accordingly, an object of this invention is to provide a variety ofsemiconductor devices for which the hermetic seal is reliable for theinterface between one or more semiconductor pellets having one or moresemiconductor device element disposed therein and being arranged thereinand a resin layer which covers the semiconductor pellet or pellets,resultantly effectively preventing humidity from contacting the metalparts of the circuits of the semiconductor device and sufficientlyprotecting the metal parts of the circuits from potential corrosion andfor which the thermal conductivity has been improved, resultantlypreventing a delay in operation speed from occurring due to atemperature rise thereof.

The other object of this invention is to provide a method for producingthe variety of semiconductor devices having the foregoing advantages.

To achieve the foregoing object, the semiconductor device in accordancewith this invention is based on a concept that one or more semiconductorpellets having one or more semiconductor device element disposed thereinare arranged on the bottom surface of a recess produced along a surfaceof a semiconductor plate having wirings arranged on the surface of thesemiconductor plate, the wirings extending toward the surface of therecess, and the recess being buried with a layer of a resin which isinclined to inflate, while it is hardened, resultantly producing amechanical stress in the resin layer in a direction to expand the resinlayer toward the side wall of the recess engraved in the semiconductorplate, resultantly preventing breakage from happening for an interfacebetween the side wall of the recess engraved in the semiconductor plateand the surface of the resin layer contacting the side wall, andremarkably improving the thermal conductivity efficiency to reduce themagnitude of a temperature rise of the semiconductor device, resultantlypreventing a delay from happening for the operation speed of thesemiconductor device.

Various embodiments itemized below are presented.

1. The connection between the bonding pads of the semiconductor pelletor pellets and the wirings can be made by bump electrodes.

2. The recess of the semiconductor plate can be made to have a multiplestep.

3. The rear surface of the semiconductor plate can be provided withplural cooling grooves arranged in parallel to each other, arranged inplural crosses or arranged in some other geometrical patterns.

4. The rear surface of the semiconductor plate can be provided with ametal plate heat sink.

To achieve the foregoing other object of this invention, the method forproducing the variety of semiconductor devices of this invention has astep for producing a recess along one surface of a semiconductor plate,a step for producing wirings extending along a surface of the recess ofthe semiconductor plate and along one surface of the semiconductorplate, either two steps consisting of a step for placing at least onesemiconductor pellet having at least one semiconductor device elementdisposed therein and having bonding pads arranged thereon and a step forconnecting the bonding pads with the wirings employing bonding wires, orone step for placing at least one semiconductor pellet having at leastone semiconductor device element disposed therein and having bondingpads arranged thereon, in a face down position to connect the bondingpads with the wirings, a step for burying the recess with a resin, and astep for producing plural electrodes along the one surface of thesemiconductor plate to connect the electrodes with the wirings.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention, together with its various features and advantages, canbe readily understood from the following more detailed descriptionpresented in conjunction with the following drawings, in which:

FIG. 1 is a cross section of a semiconductor device available in theprior art,

FIG. 2 is a cross section of a semiconductor device available in theprior art, the semiconductor device being mounted on a mother board,

FIG. 3 is a cross section of a semiconductor device in accordance withthe first embodiment of this invention,

FIG. 4 is a cross section of a semiconductor device in accordance withthe first embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 5 is a cross section of a semiconductor device in accordance withthe second embodiment of this invention,

FIG. 6 is a cross section of a semiconductor device in accordance withthe second embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 7 is a cross section of a semiconductor device in accordance withthe third embodiment of this invention,

FIG. 8 is a cross section of a semiconductor device in accordance withthe third embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 9 is a cross section of a semiconductor device in accordance withthe fourth embodiment of this invention,

FIG. 10 is a cross section of a semiconductor device in accordance withthe fourth embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 11 is a cross section of a semiconductor device in accordance withthe fifth embodiment of this invention,

FIG. 12 is a cross section of a semiconductor device in accordance withthe fifth embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 13 is a cross section of a semiconductor device in accordance withthe sixth embodiment of this invention,

FIG. 14 is a cross section of a semiconductor device in accordance withthe sixth embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 15 is a cross section of a semiconductor device in accordance withthe seventh embodiment of this invention,

FIG. 16 is a cross section of a semiconductor device in accordance h theseventh embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 17 is a cross section of a semiconductor device in accordance withthe eighth embodiment of this invention,

FIG. 18 is a cross section of a semiconductor device in accordance withthe eighth embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 19 is a cross section of a semiconductor device in accordance withthe ninth embodiment of this invention,

FIG. 20 is a cross section of a semiconductor device in accordance withthe ninth embodiment of this invention, the semiconductor device beingmounted on a mother board,

FIG. 21 is a cross section of a semiconductor device in accordance withthe tenth embodiment of this invention, and

FIG. 22 is a cross section of a semiconductor device in accordance withthe tenth embodiment of this invention, the semiconductor device beingmounted on a mother board.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to drawings, semiconductor devices in accordance with tenindependent embodiments of this invention will be described below.

First Embodiment

Referring to FIG. 3, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 made of a material e.g. a semiconductorsuch as Si having a coefficient of thermal expansion identical orsimilar to that of the material of a semiconductor pellet referred tolater. After an Al layer is produced to cover the surface of the recess18 and the surface of the Si plate 12 surrounding the recess 18, anetching process is conducted to remain patterned Al wirings 20 extendingin a radial direction.

A pellet 22 of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads 24 donot face the surface of the recess 18. A wire bonding process isconducted to connect each of the bonding pads 24 of the Si pellet 22with corresponding one of the wirings 20 produced on the Si plate 12,employing bonding wires 26.

The recess 18 is buried with a resin having characteristics to increasethe volume thereof during a hardening process. The object of the resinlayer 28 is to protect and passivate the semiconductor pellet 22. Thesurface of the resin layer 28 is made flush with the surface of the Siplate 12.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the foregoing manner, a semiconductor device 10A in accordance withthe first embodiment of this invention has been produced.

Referring to FIG. 4, the semiconductor device 10A in accordance with thefirst embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10A is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10A in accordance with thefirst embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10A is mounted on thelarger printed circuit board or the mother board 14, resultantlyreducing possibility in which the interface between the plate 12 and theresin layer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis put into practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows M and N respectively, a bettergrade can be realized for the heat dissipation efficiency.

4. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10A in accordance with the firstembodiment of this invention, because there are less possibilities inwhich humidity contacts the metal parts arranged on the semiconductorpellet 22 to cause corrosion and in which overheating of thesemiconductor device is readily prevented from occurring to resultantlysecure an improved operation speed of the semiconductor device.

Second Embodiment

Referring to FIG. 5, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 made of e.g. Si. After an Al layer isproduced to cover the surface of the recess 18 and the surface of the Siplate 12 surrounding the recess 18, an etching process is conducted toremain patterned Al wirings 20 extending in a radial direction.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads 24 facethe surface of the recess 18. Solder bump electrodes 30 are employed toconnect each of the bonding pads 24 with corresponding one of thewirings 26.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22. The surface ofthe resin layer 28 is made flush with the surface of the Si plate 12.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the foregoing manner, a semiconductor device 10B in accordance withthe second embodiment of this invention has been produced.

Referring to FIG. 6, the semiconductor device 10B in accordance with thesecond embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10B is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10B in accordance with thesecond embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10B is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a chemical stressunder which the resin layer 28 is inclined to expand. As a result, theinterface between the plate 12 and the resin layer 28 can hardly break,when being imposed thermal cycling, during a process for mounting thesemiconductor device on a larger printed circuit board or a mother board14 or during a process under which the semiconductor device is put intopractical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or a motherboard 14, passing through the plate 12 and the solder bumps 16 and theelectrodes 50, as shown by arrows M and N respectively, a better gradecan be realized for the heat dissipation efficiency.

4. Since the semiconductor pellet 22 is mounted on the surface of therecess 18 in a face down position, and since the bonding pads 24 of thesemiconductor pellet 22 are connected with the wirings 20 arranged alongthe surface of the recess 18 by solder bumps 30, a less length of timeis required for producing the semiconductor device 10B and a bettergrade of the heat dissipation efficiency is realized for thesemiconductor device 10B.

5. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10B in accordance with thesecond embodiment of this invention, because there are lesspossibilities in which humidity contacts the metal parts of thesemiconductor pellet 22 to cause corrosion and in which overheating ofthe semiconductor device is readily prevented from occurring toresultantly secure an improved operation speed for the semiconductordevice. In addition, it is noted that the length of time required forproducing the semiconductor device is less.

Third Embodiment

Referring to FIG. 7, a chemical etching process or a laser etchingprocess is conducted to produce a multi-stepped recess 18 (In thedrawings, a two stepped recess.) having a deeper recess having a smallerhorizontal dimension and being surrounded by a shallower recess having alarger horizontal dimension along one surface of a square or rectangularplate 12 of e.g. Si. After an Al layer is produced to cover the surfaceof the step and the surface of the Si plate 12 surrounding the step, anetching process is conducted to remain patterned Al wirings 20 extendingin a radial direction and having one end terminated at the edge of theshallower recess, as is illustrated in FIG. 7. In this example, theheight of the first step or the depth of the shallower recess issupposed to vary between 30 μm and 100 μm, and the height of the secondstep or the depth of the deeper recess is supposed to vary between 250μm and 580 μm. The thickness of a semiconductor pellet 22 to be referredto below is supposed to vary 200 μm and 300 μm.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads 24 donot face the surface of the recess 18. A wire bonding process isconducted to connect each of the bonding pads 24 with corresponding oneof the wirings 20, employing bonding wires 26.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10C in accordance withthe third embodiment of this invention has been produced.

Referring to FIG. 8, the semiconductor device 10C in accordance with thethird embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10C is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10C in accordance with thethird embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10C is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis put into practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or a motherboard 14, passing through the plate 12 and the solder bumps 16 and theelectrodes 50, as shown by arrows M and N respectively, a better gradecan be realized for the heat dissipation efficiency.

4. Since the recess 18 of the Si plate 12 is a multi-stepped one havinga shallow shoulder in addition to a deep bottom, additional advantagesare recognized, as follows.

A. The process for producing the wirings 20 becomes easier, because theheight of the step is less. There is a less possibility in which thewirings 20 are discontinued at an edge of the step.

B. The possibility in which a bonding wire 26 contacts with the edge ofthe semiconductor pellet 22 becomes less, because the level of thebonding pad 24 is nearly identical to that of the wiring 20 on the step.

5. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10C in accordance with the thirdembodiment of this invention, because there are less possibilities inwhich the wirings 20 discontinue and/or the bonding wires areshort-circuited with the edge of the semiconductor pellet 22, inaddition to a less magnitude of the possibility in which humiditycontacts the metal parts of the semiconductor pellet 22 to causecorrosion and in which overheating of the semiconductor device isreadily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device.

It is needless to emphasize that the number of steps to be produced forthe recess 18 is not limited to one. It can be two or three.

Fourth Embodiment

Referring to FIG. 9, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 of e.g. Si. After an Al layer is producedto cover the surface of the recess 18 and the surface of the Si plate 12surrounding the recess 18, an etching process is conducted to remainpatterned Al wirings 20 extending to the neighborhood of bonding pads 24of Si pellets 22 which are scheduled to be arranged in the recess 18.

Two or more pellets 22 made of a semiconductor e.g. Si in each of whichpellets at least one semiconductor device element has been produced andon each of which bonding pads 24 have been produced along the peripherythereof, are adhered along the surface of the recess 18 in a position inwhich the bonding pads do not face the surface of the recess 18. Thehorizontal arrangement of the Si pellets 22 in the recess 18 is entirelyfree. A wire bonding process is conducted to connect each of the bondingpads 24 with corresponding one of the wirings 20, employing bondingwires 26. The horizontal shape of the Al wirings 20 is selected to becompatible with the horizontal arrangement of the Si pellets 22 in therecess 18, in a manner to make the length of the bonding wires 26minimum.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22. The surface ofthe resin layer 28 is made flush with the surface of the Si plate 12.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10D in accordance withthe fourth embodiment of this invention has been produced.

Referring to FIG. 10, the semiconductor device 10D is mounted on alarger printed circuit board or a mother board 14. When being mounted,the semiconductor device 10D is placed on the larger printed circuitboard or the mother board 14 in a position in which each of electrodes50 printed on the larger printed circuit board or a mother board 14faces each of the solder bump electrodes 16. Thereafter, thesemiconductor device is heated at a temperature range between 150° C.and 240° C. to melt the solder bump electrodes 16.

The advantages of the semiconductor device 10D in accordance with thefifth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellets 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellets 22during the period in which the semiconductor device 10D is mounted on alarger printed circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis put into practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows M and N respectively, a bettergrade can be realized for the heat dissipation efficiency.

4. Since arbitrary Si pellets 22 having any particular function can beselected, any particular function can be readily realized by a properselection of the Si pellets 22.

5. It is noted that the length of the connection among the Si pellets 22is remarkably shorter for the semiconductor device 10D in accordancewith the fourth embodiment of this invention than for the one availablein the prior art.

6. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10D in accordance with thefourth embodiment of this invention, because there are lesspossibilities in which humidity contacts the metal parts of thesemiconductor pellets 22 to cause corrosion and in which overheating ofthe semiconductor device is readily prevented from occurring toresultantly secure an improved operation speed for the semiconductordevice. It is further noted that the semiconductor device in accordancewith the fourth embodiment of this invention 10D is involved with a goodgrade of versatility in the function thereof, as was described above.

It is noted the number of the semiconductor pellets 22 to be mounted onone Si plate 12 is entirely free.

Fifth Embodiment

Referring to FIG. 11, a chemical etching process or a laser etchingprocess is conducted to produce a two stepped recess 18 having a smallhorizontal dimension surrounded by a shallow recess having a largerhorizontal dimension along one surface of a square or rectangular plate12 of e.g. Si. An etching process such as a mechanical etching processemploying a blade, a chemical etching process or a laser etching processis conducted to produce plural grooves 34 arranged in parallel to oneanother or in an arbitrary arrangement including an arrangement in whichthe grooves cross to one another. After an Al layer is produced to coverstep and the surface of the Si plate 12 surrounding the step, an etchingprocess is conducted to remain patterned Al wirings 20 extending in aradial direction and having one end terminated at the edge of theshallow recess, as is illustrated in FIG. 11. In this example, theheight of the first step or the depth of the shallow recess is supposedto vary between 30 μm and 100 μm, and the height of the second step orthe depth of the deep recess is supposed to vary between 250 μm and 580μm. The thickness of a semiconductor pellet 22 to be referred to belowis supposed to vary 200 μm and 300 μm.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads do notface the surface of the recess 18. A wire bonding process is conductedto connect each of the bonding pads 24 with corresponding one of thewirings 20, employing bonding wires 26.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22. The surface ofthe resin layer 28 is made flush with surface of the Si plate 12.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10E in accordance withthe fifth embodiment of this invention has been produced.

Referring to FIG. 12, the semiconductor device 10E in accordance withthe fifth embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10E is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10E in accordance with thefifth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10E is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a layer printed circuit board or amother board 14 or during a process under which the semiconductor deviceis put into practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows M and N respectively, andsince the heat generated in the semiconductor device under practicalservices is dissipated into the air through the surface of the grooves34, as shown by an arrow L, a better grade can be realized for the heatdissipation efficiency.

4. Since the recess 18 of the Si plate 12 is a stepped one having ashallow shoulder in addition to a deep bottom, additional advantages arerecognized as follows.

A. The process for producing the wirings 20 becomes easier, because themagnitude of the step is less. There is a less possibility in which thewirings 20 are discontinued at an edge of the step.

B. The possibility in which a bonding wire 26 contacts the edge of thesemiconductor pellet 22, becomes less, because the level of the bondingpad 24 is nearly identical to that of the wiring 20 on the step.

5. Since the Si plate 12 has plural grooves on the top surface thereofallowing it to have a larger surface area, a larger grade of heatdissipation efficiency can be realized.

6. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10E in accordance with the fifthembodiment of this invention, because there are less possibilities inwhich the wirings 20 discontinue and/or the bonding wires areshort-circuited with the edge of the semiconductor pellet 22, inaddition to a less magnitude of the possibility in which humiditycontacts the metal parts of the semiconductor pellet 22 to causecorrosion and in which overheating of the semiconductor device isreadily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device.

Sixth Embodiment

Referring to FIG. 13, a chemical etching process or a laser etchingprocess is conducted to produce a multi-stepped recess 18 (In thedrawing, a two stepped recess) having a deep recess having a smallhorizontal dimension and being surrounded by a shallow recess having alarge horizontal dimension along one surface of a square or rectangularplate 12 of Si. A vacuum evaporation process et al. is conducted toproduce a metal layer 36 made of Au et al. along the opposite surface ofthe Si plate 12. After an Al layer is produced to cover the surface ofthe step and the surface of the Si plate 12 surrounding the step, anetching process is conducted to remain patterned Al wirings 20 extendingin a radial direction and having one end terminated at the edge of theshallow recess, as is illustrated in FIG. 13. In this example, theheight of the first step or the depth of the shallow recess is supposedto vary between 30 μm and 100 μm, and the height of the second step orthe depth of the deep recess is supposed to vary between 250 μm and 580μm. The thickness of a semiconductor pellet 22 to be referred to belowis supposed to vary 200 μm and 300 μm.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads do notface the surface of the recess 18. A wire bonding process is conductedto connect each of the bonding pads 24 with corresponding one of thewirings 20, employing bonding wires 26.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10F in accordance withthe sixth embodiment of this invention has been produced.

Referring to FIG. 14, the semiconductor device 10F in accordance withthe sixth embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10F is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10F in accordance with thefifth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10E is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis put into practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows M and N respectively, a bettergrade can be realized for the heat dissipation efficiency. In addition,since a metal layer 36 made of Au et al. is arranged on the top surfaceof the Si plate 12, the heat generated in the semiconductor device underpractical services is dissipated into the air, as shown in an arrow L,resultantly improving the heat dissipation efficiency.

4. Since the recess 18 of the Si plate 12 is a stepped one having ashallow shoulder in addition to a deep bottom, additional advantages arerecognized as follows.

A. The process for producing the wirings 20 becomes easier, because themagnitude of the step is less. There is a less possibility in which thewirings 20 are discontinued at an edge of the step.

B. The possibility in which a bonding wire 26 contacts the edge of thesemiconductor pellet 22, becomes less, because the level of the bondingpad 24 is nearly identical to that of the wiring 20 on the step.

5. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10F in accordance with the sixthembodiment of this invention, because there are less possibilities inwhich the wirings 20 discontinue and/or the bonding wires areshort-circuited with the edge of the semiconductor pellet 22, inaddition to a less magnitude of the possibility in which humiditycontacts the metal parts of the semiconductor pellet 22 to causecorrosion and in which overheating of the semiconductor device isreadily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device. In addition, it is notedthat the length of time required for producing the semiconductor deviceis less.

Seventh Embodiment

Referring to FIG. 15, a chemical etching process or a laser etchingprocess is conducted to produce a multi-stepped recess 18 along onesurface of a square or rectangular plate 12 of e.g. Si. After an Allayer is produced to cover the surface of the recess 18 and the surfaceof the Si plate 12 surrounding the recess 18, an etching process isconducted to remain patterned Al wirings 20 extending to theneighborhood of bonding pads 24 of Si pellets 22 which are scheduled tobe arranged in the recess 18.

Two or more pellets 22 made of a semiconductor e.g. Si in each of whichat least one semiconductor device element has been produced and on eachof which bonding pads 24 have been produced along the periphery thereof,are adhered along the surface of the recess 18 in a position in whichthe bonding pads face the surface of the recess 18. The number of the Sipellets 22 and the horizontal arrangement of the Si pellets 22 in therecess 18 are entirely free. Solder bump electrodes 30 are employed toconnect each of bonding pads 24 with corresponding one of the wirings 2.The horizontal shape of the Al wirings 20 is selected to be compatiblewith the horizontal arrangement of the Si pellets 22 in the recess 18,in a manner to make the length of the Al wirings 20 minimum.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the Si pellets 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10G in accordance withthe seventh embodiment of this invention has been produced.

Referring to FIG. 16, the semiconductor device 10G in accordance withthe seventh embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10G is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10G in accordance with theseventh embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellets 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellets 22during the period in which the semiconductor device 10G is mounted on alarger printed circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in a recess 18, the resin layer 28 is under a mechanical stressunder which the resin layer 28 is inclined to expand. As a result, theinterface between the plate 12 and the resin layer 28 can hardly break,when being imposed thermal cycling, during a process for mounting thesemiconductor device on a larger printed circuit board or a mother board14 or during a process under which the semiconductor device is inpractical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows M and N respectively, a bettergrade can be realized for the heat dissipation efficiency.

4. Since arbitrary Si pellets 22 having any particular function can beselected, any particular function can be realized by a proper selectionof the Si pellets 22.

5. It is noted that the length of the connection among the Si pellets 22is remarkably shorter for the semiconductor device 10G in accordancewith the seventh embodiment of this invention than for the one availablein the prior art.

6. Since the semiconductor pellets 22 are mounted on the surface of therecess 18 in a face down position, and since the bonding pads 24 of thesemiconductor pellets 22 are connected with the wirings 20 arrangedalong the surface of the recess 18 by solder bumps 30, a less length oftime is required for producing the semiconductor device 10G and a largerheat dissipation efficiency is realized for the semiconductor device10G.

7. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10G in accordance with theseventh embodiment of this invention, because there are lesspossibilities in which humidity contacts the metal parts of thesemiconductor pellets 22 to cause corrosion and in which overheating ofthe semiconductor device is readily prevented from occurring toresultantly secure an improved operation speed for the semiconductordevice. In addition, it is noted that the length of time required forproducing the semiconductor device is less.

Eighth Embodiment

Referring to FIG. 17, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 of e.g. Si. An etching process such as amechanical etching process employing a blade, a chemical etching processor a laser etching process is conducted to produce plural grooves 34arranged in parallel to one another or in an arbitrary arrangementincluding an arrangement in which the grooves cross to one another.After an Al layer is produced to cover the surface of the recess 18 andthe surface of the Si plate 12 surrounding the recess 18, an etchingprocess is conducted to remain patterned Al wirings 20 extending in aradial direction.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads facethe surface of the recess 18. Solder bump electrodes 30 are employed toconnect each of the bonding pads 24 with corresponding one of thewirings 26.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10H in accordance withthe eighth embodiment of this invention has been produced.

Referring to FIG. 18, the semiconductor device 10H in accordance withthe eighth embodiment of this invention is mounted on a larger printedcircuit board or a mother board 14. When being mounted, thesemiconductor device 10H is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10H in accordance with theeighth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10H is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis in practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the larger printed circuit board or themother board 14, passing through the plate 12 and the solder bumps 16and the electrodes 50, as shown by arrows L, M and N respectively, abetter grade can be realized for the heat dissipation efficiency.

4. Since the semiconductor pellet 22 is mounted on the surface of therecess 18 in a face down position, and since the solder bumps 30 areemployed for connecting the bonding pads 24 and the wirings 20, a lesslength of time is required for producing the semiconductor device 10Hand a larger heat dissipation efficiency is realized for thesemiconductor device 10H.

5. Since the Si plate 12 has plural grooves on the top surface thereofallowing it to have a larger surface area, a larger grade of heatdissipation efficiency can be realized.

6. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10H in accordance with theeighth embodiment of this invention, because there are lesspossibilities in which the wirings 20 discontinue and/or the bondingwires are short-circuited with the edge of the semiconductor pellet 22,in addition to a less magnitude of the possibility in which humiditycontacts the metal parts of the semiconductor pellet 22 to causecorrosion and in which overheating of the semiconductor device isreadily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device.

Ninth Embodiment

Referring to FIG. 9, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 of e.g. Si. A vacuum evaporation processet al. is conducted to produce a metal layer 36 along the surface of theSi plate 12 opposite to the surface along which the recess 18 wasproduced. After an Al layer is produced to cover the surface of therecess 18 and the surface of the Si plate 12 surrounding the recess 18,an etching process is conducted to remain patterned Al wirings 20extending in a radial direction.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads facethe surface of the recess 18. Solder bump electrodes 30 are employed toconnect each of the bonding pads 24 with corresponding one of thewirings 20.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 101 in accordance withthe ninth embodiment of this invention has been produced.

Referring to FIG. 20, the semiconductor device 101 in accordance withthe ninth embodiment of this invention is mounted on a larger printedcircuit board or the mother board 14. When being mounted, thesemiconductor device 101 is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 101 in accordance with theninth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 101 is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis in practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the air through the metal layer 36 as shownby an arrow L, in addition to the passage passing through the plate 12and the solder bumps 16 and the electrodes 50, as shown by arrows M andN respectively, a better grade can be realized for the heat dissipationefficiency.

4. Since the semiconductor pellet 22 is mounted on the surface of therecess 18 in a face down position, and since the bonding pads 24 of thesemiconductor pellet 22 are connected with the wirings 20 arranged alongthe surface of the recess 18 by solder bumps 30, a less length of timeis required for producing the semiconductor device 101 and a larger heatdissipation efficiency is realized for the semiconductor device 101.

5. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 101 in accordance with the ninthembodiment of this invention, because there are less possibilities inwhich humidity contacts the metal parts of the semiconductor pellet 22to cause corrosion and in which overheating of the semiconductor deviceis readily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device. In addition, it is notedthat the length of time required for producing the semiconductor deviceis less.

Tenth Embodiment

Referring to FIG. 21, a chemical etching process or a laser etchingprocess is conducted to produce a recess 18 along one surface of asquare or rectangular plate 12 of e.g. Si. An etching process such as amechanical etching process employing a blade, a chemical etching processor a laser etching process is conducted to produce plural grooves 34arranged in parallel to one another or in an arbitrary arrangementincluding an arrangement in which the grooves cross to one another. Avacuum evaporation process et al. is conducted to produce a metal layer36 along the surface of the Si plate 12 along which the plural grooves34 were produced. After an Al layer is produced to cover the surface ofthe recess 18 and the surface of the Si plate 12 surrounding the recess18, an etching process is conducted to remain patterned Al wirings 20extending in a radial direction.

A pellet 22 made of a semiconductor e.g. Si in which at least onesemiconductor device element has been produced and on which bonding pads24 have been produced along the periphery thereof, is adhered along thesurface of the recess 18 in a position in which the bonding pads facethe surface of the recess 18. Solder bump electrodes 30 are employed toconnect each of the bonding pads 24 with corresponding one of thewirings 20.

The recess 18 is buried with a resin. The object of the resin layer 28is to protect and passivate the semiconductor pellet 22.

Plural electrodes 16 in the form of solder bumps are produced to beconnected with the wirings 20 in a position to surround the resin layer28.

In the forgoing manner, a semiconductor device 10J in accordance withthe tenth embodiment of this invention has been produced.

Referring to FIG. 22, the semiconductor device 10J in accordance withthe tenth embodiment of this invention is mounted on a larger printedcircuit board or the mother board 14. When being mounted, thesemiconductor device 10J is placed on the larger printed circuit boardor the mother board 14 in a position in which each of electrodes 50printed on the larger printed circuit board or the mother board 14 faceseach of the solder bump electrodes 16. Thereafter, the semiconductordevice is heated at a temperature range between 150° C. and 240° C. tomelt the solder bump electrodes 16.

The advantages of the semiconductor device 10J in accordance with thetenth embodiment of this invention are itemized below.

1. Since the material of the square or rectangular plate 12 is identicalor similar to that of the semiconductor pellet 22, a thermal stress canhardly occur between the plate 12 and the semiconductor pellet 22 duringthe period in which the semiconductor device 10J is mounted on a largerprinted circuit board or a mother board 14, resultantly reducingpossibility in which the interface between the plate 12 and the resinlayer 28 breaks.

2. Since the resin layer 28 is a bulk of a resin which was hardened andinflated in the recess 18, the resin layer 28 is under a mechanicalstress under which the resin layer 28 is inclined to expand. As aresult, the interface between the plate 12 and the resin layer 28 canhardly break, when being imposed thermal cycling, during a process formounting the semiconductor device on a larger printed circuit board or amother board 14 or during a process under which the semiconductor deviceis in practical operation.

3. Since the heat generated in the semiconductor device under practicalservices is dissipated into the air through the metal layer 36 as shownby an arrow L, in addition to the passage passing through the plate 12and the solder bumps 16 and the electrodes 50, as shown by arrows M andN respectively, a better grade can be realized for the heat dissipationefficiency.

4. Since the semiconductor pellet 22 is mounted on the surface of therecess 18 in a face down position, and since the recess 18 by solderbumps 30, a less length of time is required for producing thesemiconductor device 10J and a larger heat dissipation efficiency isrealized for the semiconductor device 10J.

5. The foregoing advantages, in combination, remarkably improves thereliability of the semiconductor device 10J in accordance with the tenthembodiment of this invention, because there are less possibilities inwhich humidity contacts the metal parts of the semiconductor pellet 22to cause corrosion and in which overheating of the semiconductor deviceis readily prevented from occurring to resultantly secure an improvedoperation speed for the semiconductor device. In addition, it is notedthat the length of time required for producing the semiconductor deviceis less.

The foregoing description has clarified that the present invention hassuccessfully provided a variety of semiconductor devices for which thehermetic seal is reliable for the interface between one or moresemiconductor pellets arranged therein and a resin layer which coversthe semiconductor pellet or pellets, resultantly effectively preventinghumidity from contacting the metal parts of the circuits of thesemiconductor device and protecting the metal parts of the circuits frompotential corrosion and for which the thermal conductivity has beenimproved, resultantly preventing a delay in operation speed fromoccurring due to a temperature rise thereof, and a method for producingthe variety of semiconductor devices presented above.

Various modifications of the disclosed embodiments as well as otherembodiments of this invention, will be apparent to persons skilled inthe art upon to the description of this invention. It is thereforecontemplated that the appended claims will cover any such modificationsor embodiments as fall within the true scope of this invention.

What is claimed is:
 1. The semiconductor device comprising: asemiconductor pellet made of a semiconductor material and having bondingpads; a plate having a first surface and a second surface opposite tothe first surface, the plate being made of the semiconductor materialand having a recess formed on the first surface, and the semiconductorpellet being mounted on the recess; wirings formed on the first surfaceof the plate, the wirings extending from the recess to the first surfaceof the plate to be coupled with the bonding pads of the semiconductorpellet; a resin sealing the semiconductor pellet and a portion of thewirings; a plurality of electrodes formed on the first surface andcoupled with the wirings respectively, wherein a surface of thesemiconductor pellet on which the bonding pads are formed faces a bottomof the recess; another semiconductor pellet made of a semiconductormaterial and having bonding pads, the another semiconductor pellet beingmounted on a bottom of the same recess as said semiconductor pellet ismounted therein; and further wirings formed on the first surface of theplate, the further wirings extending from the recess to the firstsurface of the plate to be coupled with the bonding pads of the anothersemiconductor pellet.
 2. The semiconductor device in accordance withclaim 1, further comprising solder bump electrodes connecting thebonding pads of the semiconductor pellet with the wirings.
 3. Thesemiconductor device in accordance with claim 2, wherein a surface ofthe semiconductor pellet on which the bonding pads are formed is spacedaway from a bottom of the recess.
 4. The semiconductor device inaccordance with claim 1, wherein the recess is formed with multiplesteps.
 5. The semiconductor device in accordance with claim 1, whereinthe wirings extend from a bottom of the recess to the first surface ofthe plate.
 6. The semiconductor device in accordance with claim 1,wherein the second surface of the plate has a groove formed thereon. 7.The semiconductor device in accordance with claim 1, further comprisinga metal layer formed on the second surface of the plate.
 8. Thesemiconductor device in accordance with claim 1, wherein thesemiconductor material of said semiconductor pellet and of said platecomprises silicon.
 9. The semiconductor device in accordance with claim1, wherein said semiconductor pellet and said plate each have the samecoefficient of thermal expansion.
 10. The semiconductor device inaccordance with claim 1, further comprising additional wirings thatelectrically connect the semiconductor pellet and the anothersemiconductor pellet.